Ryzom before, it probably left a very unique taste in your mouth. Even after several years you would be hard-pressed to find an MMO that has such unique features as a weather system that actually affects gameplay, migrating mobs with predator/prey relationships, a skill-based system that allows players to explore many different activities, mounts and pack creatures that can actually be killed in the line of duty, and such a rich landscape, primed for roleplay! Ryzom is easily one of the favorite games of some of the staff at Massively.
For a while, the game featured a trial island on which players could achieve a fraction of the 250 max levels in the game, but that option was put to a time limit. After March 9th, however, it looks like new players will be able to not only leave the trial island but reach a max level of 125 -- after which all experience stops. Also, a player can continue to enjoy the game like this forever -- for free. It's essentially a unlimited free trial option, and it firmly places Ryzom in the freemium category. Don't forget, though, that the game continues to depend on subscriptions to make money, so feel free to use that option to unlock the entire game.
While there are still many questions, keep an eye on Massively or head to the official site to check it out. The discussion has already started on the official forums!